Writing and Naming Ionic Compounds with Changing Oxidation States (Multiple Charge Cations)

The multiple-charge cations are:  Pb 2+ /Pb 4+,  Sn 2+ /Sn 4+, transition elements (not Ag or Zn)  Ag is always 1+, Zn is always 2+

A. To name, given the formula:  1. Figure out charge on cation.  2. Write name of cation.  3. Write Roman numerals in ( )to show cation’s charge.  4. Write name of anion. Stock System of Nomenclature

 FeOFe ? O 2– iron (II) oxide  Fe 2 O 3 2 Fe ? 3 O 2– iron (III) oxide  CuBrCu ? Br 1– copper (I) bromide  CuBr 2 Cu ? 2 Br 1– copper (II) bromide  One idea that we haven’t explicitly stated yet is that the charges of the cation and anions must balance to 0.

To find the formula, given the name:  1. Write symbols for the two types of ions.  2. Balance charges to write formula.  cobalt (III) chlorideCo 3+ Cl 1– CoCl 3  tin (IV) oxideSn 4+ O 2– SnO 2  tin (II) oxideSn 2+ O 2– SnO

Traditional System of Nomenclature  …used historically (and still some today) to name compounds w /multiple-charge cations  To use:  1. Use Latin root of cation.  2. Use -ic ending for higher charge; “ -ous “ “ lower “  3. Then say name of anion, as usual.

Element Latin root -ic -ous gold, Auaur-Au 3+ Au 1+ lead, Pb plumb-Pb 4+ Pb 2+ tin, Sn stann-Sn 4+ Sn 2+ copper, Cucupr-Cu 2+ Cu 1+ iron, Feferr-Fe 3+ Fe 2+

 Write formulas:  cuprous sulfide  Cu 1+ S 2– Cu 2 S  auric nitride  Au 3+ N 3– AuN  ferrous fluoride  Fe 2+ F 1– FeF 2  Write names:  Pb 3 P 4 3 Pb ? 4 P 3–  plumbic phosphide  Pb 3 P 2 3 Pb ? 2 P 3–  plumbous phosphide  SnCl 4 Sn ? 4 Cl 1–  stannic chloride